CN102680798B - Online measurement method and device for grounding resistor of rod tower - Google Patents

Abstract

The invention provides an online measurement method and device for a grounding resistor. By using a meter clamping method, four pairs of potential transformers PT and current transformers CT are respectively connected on two anti-lightning wires at the left end and the right end of a rod tower. Voltage signals are sensed to the anti-lightning wires through the potential transformers; current signals are collected and measured, and the current signals are subjected to signal processing steps such as filtering and amplifying to obtain relation of feedback current and inductive voltage; and finally, the resistance of the grounding resistor of the rod tower to be measured is obtained by a special calculation method. With the adoption of the online measurement method and device, data measurement is carried out on the top of the rod tower. The online measurement method and device can be suitable for the rod tower containing a plurality of down leads, so that the anti-theft problem can be solved, and the grounding resistor can be rapidly and accurately measured.

Description

Pole tower ground resistance On-line Measuring Method and device

Art

The invention belongs to the technical field of high voltage of power science, relate to a kind of method and device of on-line measurement stake resistance, be applicable to the shaft tower containing many downleads, and by the remote transmission of data, the long-range of resistance can be grounded and accurately measure fast.

Background technology

Grounding resistance is the important technology index of transmission line of electricity earthed system.If the stake resistance of equipment exceeds normal range, when there is electric shock situation, can do great damage to power system device.In order to ensure that various electrical equipment utilizes electric equipment ground equipment safety reliability service, regularly measurement inspection must be carried out to the grounding resistance of earthed system by regulation.And due to transmission system shaft tower One's name is legion, on-the-spot actual measurement is carried out to the stake resistance of earthed system and just becomes very hard work, a kind of pole tower ground resistance On-line Measuring Method and device can be grounded resistance and automatically measure and data wireless is transferred to Surveillance center's computing machine, very big reduction labour intensity, reduces the electric power accident caused because equipment ground is bad and occurs.

Summary of the invention

In order to overcome in existing method of Testing Earth-Contact Resistance, tester must arrive test site, and the problem unnecessary for shaft tower downlead must untied, the present invention proposes a kind of method and device of on-line measurement stake resistance, the method and the device on the one hand stake resistance that can realize containing many downlead shaft towers are measured automatically, and the automatic remote that simultaneously can realize measurement result transfers to central server and stores.

The technical solution adopted for the present invention to solve the technical problems is: adopt split-core type meter method, four couples of voltage transformer pt summation current transformer CT are utilized to be connected on two lightning protection lines at two ends, shaft tower left and right respectively, tested shaft tower specific voltage signal is induced to by voltage transformer (VT), simultaneously measure the electric current in now lightning conducter by current transformer, and be converted to magnitude of voltage by current/voltage modular converter, again by filtration module filtering, range is selected by range handover module according to measured size, be DC quantity by AC-DC conversion module converts again and measure its size, be converted to digital quantity through AD conversion module and send into MCU unit, obtain the relation of voltage and electric current, eventually through specific computing method, obtain the stake resistance resistance of tested shaft tower, the method is without the need to considering tower grounding number of leads, be applicable to the shaft tower containing many downleads arbitrarily.

The method of measurement of Grounding Resistance of the present invention, adopts specific computing method, if Z is tested pole tower ground resistance resistance value, and Z _lfor left side all shaft tower parallel equivalent resistance resistance value, Z ₁and Z ₂be respectively two lightning protection line equivalent resistance resistance values between tested shaft tower and left side first order shaft tower, Z _rfor right side all shaft tower parallel equivalent resistance resistance value, Z ₃and Z ₄be respectively two lightning protection line equivalent resistance resistance values between tested shaft tower and right side first order shaft tower, as shown in Figure 1.

First carry out first time to measure, in schematic diagram, position applies voltage by voltage transformer (VT) respectively utilize current transformer to measure current generatedly in corresponding branch road to be simultaneously following matrix equation can be obtained:

$\left[\begin{array}{ccccccc}{\stackrel{\·}{I}}_1& 0& 0& 0& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_3& 0& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2+{\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4\\ 0& {\stackrel{\·}{I}}_2& 0& 0& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2& 0& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2+{\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4\\ 0& 0& {\stackrel{\·}{I}}_3& 0& 0& {\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2+{\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4\\ 0& 0& 0& {\stackrel{\·}{I}}_4& 0& {\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2+{\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4\end{array}\right]\left[\begin{array}{c}{Z}_1\\ Z_2\\ Z_3\\ Z_4\\ Z_L\\ Z_R\\ Z\end{array}\right]=\left[\begin{array}{c}{\stackrel{\·}{U}}_1\\ {\stackrel{\·}{U}}_2\\ {\stackrel{\·}{U}}_3\\ {\stackrel{\·}{U}}_4\end{array}\right]$

This non trivial solution is not unique, cannot determine circuit parameter, therefore, need carry out second time and measure.Second time measuring voltage is applied after the same method in same position and again measure and current generatedly in each corresponding branch road be be supplemented in above formula:

$\left[\begin{array}{ccccccc}{\stackrel{\·}{I}}_1& 0& 0& 0& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2& 0& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2+{\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4\\ 0& {\stackrel{\·}{I}}_2& 0& 0& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2& 0& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2+{\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4\\ 0& 0& {\stackrel{\·}{I}}_3& 0& 0& {\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2+{\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4\\ 0& 0& 0& {\stackrel{\·}{I}}_4& 0& {\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2+{\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4\\ {{\stackrel{\·}{I}}_1}^{\′}& 0& 0& 0& {{\stackrel{\·}{I}}_1}^{\′}+{{\stackrel{\·}{I}}_2}^{\′}& 0& {{\stackrel{\·}{I}}_1}^{\′}+{{\stackrel{\·}{I}}_2}^{\′}+{{\stackrel{\·}{I}}_3}^{\′}+{{\stackrel{\·}{I}}_4}^{\′}\\ 0& {{\stackrel{\·}{I}}_2}^{\′}& 0& 0& {{\stackrel{\·}{I}}_1}^{\′}+{{\stackrel{\·}{I}}_2}^{\′}& 0& {{\stackrel{\·}{I}}_1}^{\′}+{{\stackrel{\·}{I}}_2}^{\′}+{{\stackrel{\·}{I}}_3}^{\′}+{{\stackrel{\·}{I}}_4}^{\′}\\ 0& 0& {{\stackrel{\·}{I}}_3}^{\′}& 0& 0& {{\stackrel{\·}{I}}_3}^{\′}+{{\stackrel{\·}{I}}_4}^{\′}& {{\stackrel{\·}{I}}_1}^{\′}+{{\stackrel{\·}{I}}_2}^{\′}+{{\stackrel{\·}{I}}_3}^{\′}+{{\stackrel{\·}{I}}_4}^{\′}\\ 0& 0& 0& {{\stackrel{\·}{I}}_4}^{\′}& 0& {{\stackrel{\·}{I}}_3}^{\′}+{{\stackrel{\·}{I}}_4}^{\′}& {{\stackrel{\·}{I}}_1}^{\′}+{{\stackrel{\·}{I}}_2}^{\′}+{{\stackrel{\·}{I}}_3}^{\′}+{{\stackrel{\·}{I}}_4}^{\′}\end{array}\right]\left[\begin{array}{c}{Z}_1\\ Z_2\\ Z_3\\ Z_4\\ Z_L\\ Z_R\\ Z\end{array}\right]=\left[\begin{array}{c}{\stackrel{\·}{U}}_1\\ {\stackrel{\·}{U}}_2\\ {\stackrel{\·}{U}}_3\\ {\stackrel{\·}{U}}_4\\ {{\stackrel{\·}{U}}_1}^{\′}\\ {{\stackrel{\·}{U}}_2}^{\′}\\ {{\stackrel{\·}{U}}_3}^{\′}\\ {{\stackrel{\·}{U}}_4}^{\′}\end{array}\right]$

Analysis circuit, in conjunction with relevant knowledge, can obtain conclusion: when meeting

$\frac{{{\stackrel{\·}{U}}_1}^{\′}{Z}_2+{U_2}^{\′}{Z}_1}{{\stackrel{\·}{U}}_1{Z}_2+{\stackrel{\·}{U}}_2{Z}_1}\≠\frac{{{\stackrel{\·}{U}}_3}^{\′}{Z}_4+{U_4}^{\′}{Z}_3}{U_3{Z}_4+U_4+Z_3}$

Time, non trivial solution exists and uniquely, solving equation, can determine circuit parameter.If the stake resistance of shaft tower is Rg, then Rg=Re (Z).

The device of on-line measurement stake resistance of the present invention, its hardware is configured to four annular voltage transformer (VT) (PT), four ring current transformers (CT) and earth resistance tester composition.Wherein, earth resistance tester is by MCU unit (1), signal generating module (2), current/voltage modular converter (3), signal amplification module (4), signal selection module (5), power amplifier module (6), voltage transformer (VT) (7), current transformer (8), current/voltage modular converter (9), filtration module (10), range handover module (11), AC-DC conversion module (12), AD conversion module (13), display module (14), serial port module (15), clock module (16), memory module (17), GPRS module (18), power module (19) forms, wherein power module (19) adopts solar panel to power, be responsible for each chip of whole system and required voltage is provided, the master controller that MCU unit (1) is system, signal generating module (2) sends sinusoidal ac signal and by current/voltage modular converter (3), signal amplification module (4) exports the sinusoidal ac signal determining magnitude of voltage, by signal selection module (5), different magnitudes of voltage being dispensed to No. four voltage transformer (VT) again exports in branch road, simultaneously improve the load driving force of circuit thus driving voltage mutual inductor (7) by power amplifier module (6), when being induced to tested loop voltage signal by voltage transformer (VT), generation current is answered in loop, respectively four road current signals are detected by four current transformers (8), and be converted to magnitude of voltage by current/voltage modular converter (9), again by filtration module (10) filtering, range is selected by range handover module (11) according to measured size, be converted to DC quantity by AC-DC conversion module (12) and measure its size again, be converted to digital quantity through AD conversion module (13) and send into MCU unit, its earth resistance numerical value is by display module (14) display or be sent to Surveillance center's computing machine by GPRS module (18) is long-range, in the use of equipment, as parameter need be adjusted and program realizes by serial port module (15), clock module (16) is for the certainty annuity time, memory module (17) is for stores it.

The invention has the beneficial effects as follows, the long-range Quick Measurement of pole tower ground resistance can be realized, avoid the hard work that tester must reach the spot, this equipment is applicable to the shaft tower in containing many downleads arbitrarily simultaneously, without the need to untiing unnecessary downlead, alleviate the labour intensity of staff.

Accompanying drawing explanation

Fig. 1, entire system schematic diagram

1 be monitoring center's computing machine, 2 be pole tower ground resistance tester in figure, 3 for tested shaft tower

Fig. 2, equipment scheme of installation

Fig. 3, adopts the method test equivalent circuit diagram

Fig. 4, pole tower ground resistance tester principle schematic

1MCU unit, 2 signal generating module, 3 current/voltage modular converters, 4 signal amplification modules, 5 signal selection module, 6 power amplifier modules, 7 voltage transformer (VT), 8 current transformer 9 current/voltage modular converters, 10 filtration modules, 11 range handover modules, 12 AC-DC conversion modules, 13AD modular converter, 14 display modules, 15 serial port module, 16 clock modules, 17 memory modules, 18GPRS module, 19 power modules in figure

Specific embodiments

Should be as shown in Figure 2 during erecting equipment, four pairs of voltage transformer (VT) current transformers should be installed on two lightning conducters respectively, and are installed on shaft tower both sides respectively, during installation should as far as possible near the company of shaft tower and lightning conducter by locating, and magnetic circuit should be made tightly to close, to reduce error; Pole tower ground resistance tester distance voltage transformer (VT) current transformer should be too not far away, and be firmly installed on shaft tower; Solar panel should be positioned on shaft tower by production firm's requirement.

Fig. 3 is the equivalent circuit diagram of electric power line pole tower, and wherein, Z is the stake resistance resistance value of shaft tower at the corresponding levels.The program of this algorithm has been built in the MCU unit of earth resistance tester, only need measure induction current in shaft tower on request, and data are sent into MCU unit, stake resistance resistance.

Fig. 4 is pole tower ground resistance In-circiut tester principle schematic, wherein power module (19) adopts solar panel to power, be responsible for each chip of whole system and required voltage is provided, the master controller that MCU unit (1) is system, signal generating module (2) sends sinusoidal ac signal and by current/voltage modular converter (3), signal amplification module (4) exports the sinusoidal ac signal of at particular voltage level, by signal selection module (5), different magnitudes of voltage being dispensed to No. four voltage transformer (VT) again exports in branch road, simultaneously improve the load driving force of circuit thus driving voltage mutual inductor (7) by power amplifier module (6), when being induced to tested loop voltage signal by voltage transformer (VT), generation current is answered in loop, respectively four road current signals are detected by four current transformers (8), and be converted to magnitude of voltage by current/voltage modular converter (9), again by filtration module (10) filtering, range is selected by range handover module (11) according to measured size, be converted to DC quantity by AC-DC conversion module (12) and measure its size again, be converted to digital quantity through AD conversion module (13) and send into MCU unit, , and calculate stake resistance resistance, its earth resistance numerical value is by display module (14) display or be sent to Surveillance center's computing machine by GPRS module (18) is long-range, in the use of equipment, as parameter need be adjusted and program realizes by serial port module (15), clock module (16) is for the certainty annuity time, memory module (17) is for stores it.

Specific works step is as follows:

1, given an order by centralized monitoring computer, and by GPRS module, order is sent to pole tower ground resistance tester, starting outfit.

2, send sine voltage signal by pole tower ground resistance tester to voltage transformer (VT), and this alternating voltage is induced to lightning conducter.

3, meanwhile, responded to the electric current obtained in lightning conducter by current transformer, and send into pole tower ground resistance tester.

4, inner at pole tower ground resistance tester, this electric current is carried out a series of Treatment Analysis, obtains current value, current value is sent into MCU unit.

5, by MCU unit according to specific program solving equation, draw stake resistance resistance.

6, stake resistance resistance is sent to centralized monitoring computer by GPRS module, and data are stored.

Claims (3)

1. the method for an on-line measurement stake resistance, adopt split-core type meter method, four couples of voltage transformer pt summation current transformer CT are utilized to be connected on two lightning protection lines at two ends, shaft tower left and right respectively, measure and obtain the relation of electric current and voltage, eventually through specific computing method, obtain the stake resistance resistance of tested shaft tower, wherein form a pair by a voltage transformer pt and a Current Transmit, it is four right to have, described four couples of voltage transformer pt summation current transformer CT are on average arranged on two ends, shaft tower left and right, namely left end arrange two right, it is two right that right-hand member is arranged, it is characterized in that, PT is for generation of induced voltage signal, CT is for measuring the current signal generated by induced voltage, the method is without the need to considering tower grounding number of leads, be applicable to the shaft tower containing many downleads arbitrarily,

Adopt specific computing method, if Z is tested pole tower ground resistance resistance value, Z _lfor left side all shaft tower parallel equivalent resistance resistance value, Z ₁and Z ₂be respectively two lightning protection line equivalent resistance resistance values between tested shaft tower and left side first order shaft tower, Z _rfor right side all shaft tower parallel equivalent resistance resistance value, Z ₃and Z ₄be respectively two lightning protection line equivalent resistance resistance values between tested shaft tower and right side first order shaft tower, for being induced to the magnitude of voltage of shaft tower by PT, simultaneously current generatedly in corresponding branch road be following matrix equation can be obtained:

$\left[\begin{array}{ccccccc}{\stackrel{\·}{I}}_1& 0& 0& 0& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2& 0& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2+{\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4\\ 0& {\stackrel{\·}{I}}_2& 0& 0& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2& 0& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2+{\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4\\ 0& 0& {\stackrel{\·}{I}}_3& 0& 0& {\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2+{\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4\\ 0& 0& 0& {\stackrel{\·}{I}}_4& 0& {\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2+{\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4\end{array}\right]\left[\begin{array}{c}{Z}_1\\ Z_2\\ Z_3\\ Z_4\\ Z_L\\ Z_R\\ Z\end{array}\right]=\left[\begin{array}{c}{\stackrel{\·}{U}}_1\\ {\stackrel{\·}{U}}_2\\ {\stackrel{\·}{U}}_3\\ {\stackrel{\·}{U}}_4\end{array}\right]$

This non trivial solution is not unique, cannot determine circuit parameter, therefore, need carry out second time and measure; If second time is measured additional power source and is respectively current generatedly in each corresponding branch road be be supplemented in above formula:

$\left[\begin{array}{ccccccc}{\stackrel{\·}{I}}_1& 0& 0& 0& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2& 0& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2+{\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4\\ 0& {\stackrel{\·}{I}}_2& 0& 0& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2& 0& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2+{\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4\\ 0& 0& {\stackrel{\·}{I}}_3& 0& 0& {\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2+{\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4\\ 0& 0& 0& {\stackrel{\·}{I}}_4& 0& {\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4& {\stackrel{\·}{I}}_1+{\stackrel{\·}{I}}_2+{\stackrel{\·}{I}}_3+{\stackrel{\·}{I}}_4\\ {{\stackrel{\·}{I}}_1}^{\′}& 0& 0& 0& {{\stackrel{\·}{I}}_1}^{\′}+{{\stackrel{\·}{I}}_2}^{\′}& 0& {{\stackrel{\·}{I}}_1}^{\′}+{{\stackrel{\·}{I}}_2}^{\′}+{{\stackrel{\·}{I}}_3}^{\′}+{{\stackrel{\·}{I}}_4}^{\′}\\ 0& {{\stackrel{\·}{I}}_2}^{\′}& 0& 0& {{\stackrel{\·}{I}}_1}^{\′}+{{\stackrel{\·}{I}}_2}^{\′}& 0& {{\stackrel{\·}{I}}_1}^{\′}+{{\stackrel{\·}{I}}_2}^{\′}+{{\stackrel{\·}{I}}_3}^{\′}+{{\stackrel{\·}{I}}_4}^{\′}\\ 0& 0& {{\stackrel{\·}{I}}_3}^{\′}& 0& 0& {{\stackrel{\·}{I}}_3}^{\′}+{{\stackrel{\·}{I}}_4}^{\′}& {{\stackrel{\·}{I}}_1}^{\′}+{{\stackrel{\·}{I}}_2}^{\′}+{{\stackrel{\·}{I}}_3}^{\′}+{{\stackrel{\·}{I}}_4}^{\′}\\ 0& 0& 0& {{\stackrel{\·}{I}}_4}^{\′}& 0& {{\stackrel{\·}{I}}_3}^{\′}+{{\stackrel{\·}{I}}_4}^{\′}& {{\stackrel{\·}{I}}_1}^{\′}+{{\stackrel{\·}{I}}_2}^{\′}+{{\stackrel{\·}{I}}_3}^{\′}+{{\stackrel{\·}{I}}_4}^{\′}\end{array}\right]\left[\begin{array}{c}{Z}_1\\ Z_2\\ Z_3\\ Z_4\\ Z_L\\ Z_R\\ Z\end{array}\right]\left[\begin{array}{c}{\stackrel{\·}{U}}_1\\ {\stackrel{\·}{U}}_2\\ {\stackrel{\·}{U}}_3\\ {\stackrel{\·}{U}}_4\\ {{\stackrel{\·}{U}}_1}^{\′}\\ {{\stackrel{\·}{U}}_2}^{\′}\\ {{\stackrel{\·}{U}}_3}^{\′}\\ {{\stackrel{\·}{U}}_4}^{\′}\end{array}\right]$

Solving equation, can determine circuit parameter.

2. adopt the device of the on-line measurement stake resistance of method described in claim 1, it is characterized in that: by four voltage transformer pts, four Current Transmits and earth resistance tester composition, earth resistance tester is by MCU unit (1), signal generating module (2), first current/voltage modular converter (3), signal amplification module (4), signal selection module (5), power amplifier module (6), second current/voltage modular converter (9), filtration module (10), range handover module (11), AC-DC conversion module (12), AD conversion module (13), display module (14), serial port module (15), clock module (16), memory module (17), GPRS module (18), power module (19) forms, wherein power module (19) is responsible for each chip of earth resistance tester and provides required voltage, the master controller that MCU unit (1) is earth resistance tester, signal generating module (2) sends sinusoidal ac signal and by the first current/voltage modular converter (3), signal amplification module (4) exports the sinusoidal ac signal of at particular voltage level, by signal selection module (5), different magnitudes of voltage being dispensed to different voltage transformer pts again exports in branch road, simultaneously improve the load driving force of circuit thus driving voltage mutual inductor PT by power amplifier module (6), when being induced to tested loop voltage signal by voltage transformer pt, generation current is answered in loop, by Current Transmit, this current signal is detected, and be converted to magnitude of voltage by the second current/voltage modular converter (9), again by filtration module (10) filtering, range is selected by range handover module (11) according to measured size, be converted to DC quantity by AC-DC conversion module (12) and measure its size again, be converted to digital quantity through AD conversion module (13) and send into MCU unit, and calculate stake resistance resistance, its earth resistance numerical value by display module (14) display or GSM/GPRS module (18) teletransmission to Surveillance center's computing machine, serial port module (15) is for commissioning device, clock module (16) is for the certainty annuity time, memory module (17) is for stores it.

3. the device of on-line measurement stake resistance as claimed in claim 2, is characterized in that: by GSM/GPRS module (18) teletransmission to Surveillance center's computing machine.